1. Field of the Invention
The present invention relates generally to fiber optic couplers and, more particularly, to a high resolution, rugged, multichannel, low-loss fiber optic coupler for use in optical data transmission systems and method of its manufacture.
2. The Prior Art
Optical fibers have been used extensively in medical and scientific instruments, such as for example, in endoscopes and cystoscopes. More recently, optical fibers have found ever increasing applications in optical communications. Light transmitted down an optical fiber is equivalent to an electrical signal passing down a conventional copper wire. The optical fiber possesses many advantages over the copper wire, however. These advantages include a greater information carrying capacity, a complete freedom from electrical or magnetic interference, and considerable reductions in size and weight. For example, a single optical fiber can transmit simultaneously many thousand telephone conversations. The optical fiber must be able to transmit light with little attenuation, at times over great distances of hundreds or even thousands of meters. This presents little problem so long as there is no requirement for a break in the optical fiber, such as at points of coupling, due to the near total internal reflection exhibited by the optical fiber. A communication system requires couplings, however. Some of these couplings are in hostile environments. For instance, a coupling may be required to a spacecraft in space or to a submarine deep in the ocean. It is at these couplings that attenuations occur. Most of the attenuations are the result of misalignment of the respective ends of the abutting optical fibers. Since optical fibers are very thin, with an average core diameter varying between 50 and 100 micrometer, the task of properly aligning their abutting ends, especially in a multichannel coupler, is an exacting one. In addition, the coupler must be structurally rugged, yet of relatively small size and weight. The coupler also must be cost effective.
Presently, fiber optic couplers rely, for the most part, either on precision machined components or on precisely molded components, or a combination thereof. Despite the high costs involved in these processes, the resultant fiber optic couplers nevertheless have been less than satisfactory. Most of these fiber optic couplers exhibit unacceptable levels of attenuation. This problem of high degree of attenuation places a real burden on communication systems employing optical fibers and couplers.